Food emulsions, lipid oxidation

Let MB, Jacobsen C, Soerensen A-DM, Meyer AS (2007) Homogenization conditions affect the oxidative stability of fish oil enriched milk emulsions Lipid oxidation. Journal of Agricultural and Food Chemistry 55 1773-1780. 

Chaiyasit, W., Silvestre, M.P.C., McClements, D.J., Decker, E.A. (2000). Ability of surfactant hydrophobic tail group size to alter lipid oxidation in oil-in-water emulsions. Journal of Agricultural and Food Chemistry, 48, 3077-3080. 

Key Concepts of Interfacial Properties in Food Chemistry CASE STUDY LIPID OXIDATION OF EMULSIONS The case of lipid oxidation in an emulsified system is a perfect example to illustrate the importance of interfacial properties in food chemistry. The goal of this case study is not to completely describe the very complex mechanisms of lipid oxidation in emulsions. Indeed, many investigators over the past years have focused on this research area. Instead, the key interfacial parameters that influence lipid oxidation in emulsions are emphasized. 

Mei, L., McClements, D.J., Wu, J., and Decker, E.A. 1998a. Iron-catalyzed lipid oxidation in emulsion as affected by surfactant, pH and NaCl. Food Chem. 61 307-312. 

Mei, L., Decker, E.A., and McClements, D.J. 1998b. Evidence of iron association with emulsion droplets and its impact on lipid oxidation. J. Agric. Food Chem. 46 5072-5077. 

McClements D.J., and Decker E.A. (2000). Lipid oxidation in oil-in-water emulsions impact of molecular environment on chemical reactions in heterogeneous food systems. J. Food Sci. 65, 1270-1282. 

As previously mentioned, tocopherols/tocotrienols may be added to foods for the stabilization of their polyunsaturated fatty acids. Chemical conditions and the physical state of the food to be stabilized have a major influence on lipid oxidation and antioxidant reactions. The number of possible reaction routes and stabilizing and destabilizing factors is enormous (e.g., Pokorny, 1987 Warner, 1997 Frankel, 1998). In foods, tocopherols can be regenerated from their tocopheroxyl radicals by reducing compounds such as ascorbic acid. Regeneration is possible only if the lipid-soluble tocopheroxyl radical and the water-soluble ascorbic acid are close enough to be able to react with each other, e.g., in emulsion. Thus, the interfacial region between lipid and water phases is important for the antioxidant action of tocopherols and tocotrienols (Frankel, 1998). 

Osborn, H. T. and Akoh, C. C. (2004). Effect of emulsifier type, droplet size, and oil concentration on lipid oxidation in structured lipid-based oil-in-water emulsions. Food Chem. 84, 451—456. 

Physical Aspects— Lipid Oxidation in Food Emulsions.153... 

Physical Aspects—Lipid Oxidation in Food Emulsions... 

Because many foods are emulsified materials (e.g., milk, mayonnaise, coffee creamers, salad dressings, butter, and baby foods), an understanding of the mechanisms of lipid oxidation in emulsions is crucial for the formulation, production, and storage of food products. Oil-in-water emulsions consist of three different components water (the continuous phase), oil (the dispersed phase), and surface-active agent (the interface). 

Coupland, I.N. and McClements, J.D. Lipid oxidation in food emulsions. Trends in Food Science and Technology, 7, 83-91. 1996. 

In natural food systems, the interaction of tocopherols and ascorbic acid occurs favorably because initiation of lipid oxidation occurs also by metal catalysts present in the water phase. Mixtures of tocopherols with rosemary extracts (Section 3) are also synergistic in bulk oil resulting probably by their mutual reinforcing activity. Although j8-carotene when used alone in bulk and emulsion systems is either inactive or acts as a prooxidant, it becomes a good... 

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